Monkian is the leader of the Monkians of planet Plun-Darr. Always standing with a slight hunch, this anthropomorphic ape has thick white fur covering his neck and shoulders. Together with Vultureman, Monkian forms the evil gang known as the Mutants who are mostly led Jackalman and Slithe.
Endowed with more brawn than brains, Monkian is usually regarded by his name; strong and muscular physique coupled with a variety of weapons. When he has the other Mutants, Monkian will attack the ThunderCats.
His physical strength and natural simian agility mean that he is unmatched when it comes to travelling quickly through the trees. He can cover large distances in the blink of an eye by climbing and swinging between trees, always be next to Jackalman.
Because of his treetop skills, Monkian is usually Slithe's go-to Mutant when it comes to reconnaissance. Monkian can quickly and quietly scamper through forests and vegetation in order to eavesdrop on the ThunderCats. On a number of occasions, he has spied on the ThunderCats and then relayed the information to Slithe and Jackalman.
While not the most ambitious of the Mutants, since only once, Monkian nevertheless will not pass up the opportunity to gain power. This was made evident when Mumm-Ra offered to share the entire northern sector of Third Earth with the Mutant if he can bring him the Eye of Thundera. Armed with the Spheres of Power, and with all the hate that he keeps, Monkian succeeded in doing so and even defeating to crush them to kill the ThunderCats, but his greed eventually led to his failure when he tried to challenge Mumm-Ra.
Monkian was eventually apprehended by Captain Bragg and, along with his fellow Mutants, was banished for good to the distant planet of Way Outback.